Influence of the Fluorination of CoPc on the Interfacial Electronic Structure of the Coordinated Metal Ion

Abstract

Interface properties of CoPc and CoPcF16 on Cu-intercalated graphene/Ni(111) were investigated by X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), and X-ray absorption spectroscopy (XAS). We show that a charge transfer from graphene/Ni(111) to the Co ion of CoPc can be significantly reduced by Cu-intercalation of graphene, resulting in a partial decoupling of graphene from the Ni(111) substrate. This is not the case for CoPcF16 on Cu-intercalated graphene/Ni(111). Possible reasons and charge transfer channels are discussed. The comparison to CoPcF16 on the almost fully decoupled Au-intercalated graphene/Ni(111) suggests that the graphene-substrate coupling in the case of Cu-intercalation remains still significant.

FePc and FePcF16 on Rutile TiO2(110) and (100): Influence of the Substrate Preparation on the Interaction Strength

“…The spectral shape of the C 1s core-level spectra differs from C 1s of FePc due to the additional C-F bonds, visible as components at higher BE and a corresponding satellite, denoted C-3 and S C-3 in Figure 11c. The peak fit is in good agreement to C 1s spectra of related fluorinated phthalocyanines [17,52]. Most important, analogously to FePc on rutile TiO 2 (100), the spectral shape of all core-level spectra is almost independent of the film thickness.…”

“…Data are shown as Supplementary Materials (Figure S6). The increased ionization potential of fluorinated phthalocyanines may support an electron transfer to the molecule at interfaces, as shown for CoPc and CoPcF 16 on Cu-intercalated graphene/Ni(111) [17]. Therefore, we studied interface properties at the example of FePcF 16 /rutile TiO 2 (100).…”

“…It was reported that the rutile TiO 2 (100) surface is more reactive compared to rutile TiO 2 (110), since, for example, water dissociation is observed on rutile TiO 2 (100) surfaces, whereas most studies agree that on rutile TiO 2 (110) surfaces, such a chemical reaction can occur only at oxygen vacancies [14][15][16]. The fluorination of FePc results in a higher ionization potential, which may increase the ability for an electron transfer to the molecule at the interface, similar to CoPc/CoPcF 16 [17]. The crystal structures of the studied rutile surfaces are shown in Figure 1, together with the chemical structure of the molecules.…”

Interaction Channels Between Perfluorinated Iron Phthalocyanine and Cu(111)

“…Depending on the transition metal and the substrate, TMPcs may show distinct interactions at the interface, affecting also the magnetic and electronic properties at the interface to the substrate . Different interaction channels are known for phthalocyanines, involving both the central metal atom and the macrocycle – in many cases the charge transfer is expected to be bidirectional . Due to its flexibility in the spin ground state, iron complexes might be of particular interest in the view of electronic properties .…”

“…For applications, perfluorinated TMPcs have shown high stability and performance in air and they are used as n‐type channels in electronic devices . The fluorination allows a tuning of electronic properties such as the ionization potential of the molecule and may affect interface properties such as dipoles and/or charge transfer distinctly …”